Don't you just love the way a forum like this gets you thinking about expressions you've used unquestioningly for your whole life?

English appears to have little consistency (so what's new) in the use of the possessive for edible animal products. We say "chicken wings" and "turkey breast" but then "frogs' legs". The only distinction I could come up with, and it's a stretch, is that "chicken" in "chicken wings" is a reference to the meat, not the animal - i.e. wings made of that stuff we call chicken - in the same way as we would say beef steak or mutton backstraps. The word frog - despite the best efforts of the French - has never made the jump to dual usage, so we talk about the legs of the animal. "Lamb's brains" follows the "frog rule" because we don't think of its brain as being made of the meat called lamb. I'm sure that someone will rise to the challenge and find some exceptions.

Well, well. I was about to submit this, but then I thought - what about "chicken liver", "ox tongue" or "kangaroo tail" soup? Never mind, I've done so much work to type this, you may as well read this tripe. Ox tripe?.....ox's tripe?.....oxen's tripe?.....Time for your lie-down, Marty.